Twin feed ammunition conveyor for feeding shells to an automatic weapon

ABSTRACT

A twin feed ammunition conveyor for feeding shells to an automatic weapon from either of two strips of shackled shells comprises a structure having a longitudinal plane of symmetry. The structure includes an extraction station which receives the strips of shells on respective sides of the plane of symmetry, and in which the shells of each strip are separated from their shackles by a forward displacement into a respective standby location in a distribution station having a central introduction location from which the shells are fed to a shell chamber of the weapon. Means for conveying a shell from the standby locations to the central introduction location comprise two selectively driven rotors each having a pair of axially spaced star wheels operative to engage a shell in the respective standby location and to move it towards the introduction location. Radially slidable pushers on the rotor are guided by cam means to push the shell positively into the introduction location where it is held by a pair of cooperating pushers, one on each rotor, the motion of the rotor effecting the transfer being locked by a pawl upon the arrival of the shell in the introduction location.

United States Patent [191 Pierre et al.

[ Nov.4,1975

[ TWIN FEED AMMUNITION CONVEYOR FOR FEEDING SHELLS TO AN AUTOMATIC WEAPON [75] Inventors: Bernard Pierre, Lyon; Rene Volle,

Bourges; Georges Simon, St-Germain-du-Puy, all of France [73] Assignee: Etat Francais, Paris, France [22] Filed: Mar. 25, 1974 [21] Appl. No.: 454,760

[30] Foreign Application Priority Data Apr. 3, 1973 France 73.11865 [52] U.S. Cl 89/33 SF; 89/33 CA [51] Int. Cl. F41D 9/02 [58] Field of Search 89/33 BC, 33 CA, 33 SF [56] References Cited UNITED STATES PATENTS 3,793,921 2/1974 Meier et al 89/33 CA FOREIGN PATENTS OR APPLICATIONS 1,572,169 5/1969 France 89/33 SF Primary Examiner-Stephen C. Bentley Attorney, Agent, or FirmLarson, Taylor and Hinds [57] ABSTRACT A twin feed ammunition conveyor for feeding shells to an automatic weapon from either of two strips of shackled shells comprises a structure having a longitudinal plane of symmetry. The structure includes an extraction station which receives the strips of shells on respective sides of the plane of symmetry, and in which the shells of each strip are separated from their shackles by a forward displacement into a respective standby location in a distribution station having a central introduction location from which the shells are fed to a shell chamber of the weapon. Means for conveying a shell from the standby locations to the central introduction location comprise two selectively driven rotors each having a pair of axially spaced star wheels operative to engage a shell in the respective standby location and to move it towards the introduction location. Radially slidable pushers on the rotor are guided 5 Claims, 10 Drawing Figures US. Patent Nov. 4, 1975 Sheet 1 of5 3,916,762

Sheet 2 of 5 3,916,762

US. Patent Nov. 4, 1975 US. Patent Nov. 4, 1975 Sheet 4 of5 3,916,762

fi I g CE] 4 E! Fly. 6. 3 CE] US. Patent N0v.4,1975 Sheet50f5 3,916,762 I TWIN FEED AMMUNITION CONVEYOR FOR FEEDING SHELLS TO AN AUTOMATIC WEAPON This invention relates to an ammunition conveyor for feeding an automatic weapon from one or other of two strips of shackled shells, generally of different natures (one strip of armour-piercing shells and one strip of explosive shells, for instance), such ammunition conveyor having a selector mechanism enabling the gunner to select which of the two strips of shells will be set in motion by the ammunition conveyor when firing starts.

The invention relates more particularly but not exclusively to an ammunition conveyor for a twin feed automatic weapon of small or medium calibre i.e., of a calibre between 12 and 50 mm.

A known ammunition conveyor of the above kind comprises two star wheel rotors adapted to cooperate respectively with the two strips of shells, the selector mechanism in this case enabling the gunner to couple at choice one or other of the rotors to a common drive device actuated by a mobile part of the weapon.

It has already been suggested, inter alia in French Pat. No. 1,572,169, to make an ammunition conveyor which comprises firstly, at the region where the two strips of shackled shells enter the ammunition conveyor, an extraction station at which the end upstream shell of the strip of shells in use is extracted from its shackle by a longitudinal displacement produced by a pusher borne by a longitudinally reciprocating member of the automatic weapon breechmechanism, and secondly, forwardly of such extraction station, a distribution station comprising a central introduction location adapted to receive the first shell to be introduced into the barrel of the weapon and two lateral standby locations disposed symmetrically on respective sides of the central introduction location, each of the standby locations corresponding to one of the rotors of the ammunition conveyor (and therefore to one of the strips of shells) and being adapted to receive a shell of the corresponding strip coming from the extraction station.

To clarify the description, an ammunition conveyor of the last-mentioned type will be referred to hereinafter as a twin feed ammunition conveyor with two rotors and a forward distribution station.

The invention relates to an ammunition conveyor of this kind having a forward distribution station which is improved in comparison with the prior art, as regards the conveying means to be provided at such distribution station to cause a shell coming from the strip in use to move out of the lateral standby location which it occupies into the central introduction location from which it is taken over by the breech of the weapon to be introduced into the shell chamber and then fired.

In the prior art, as represented by the aforementioned French Pat. No. 1,572,169, the conveying means provided at the distributing station comprises, on respective sides of the central introduction location, two star wheels on the two rotors of the ammunition conveyor respectively (each of the star wheels engag 6 curacy in the process of moving shells between one of the standby locations and the introduction location, such inaccuracy, due to the presence of springs, possibly in extreme cases causing firing accidents if the posi' tioning should be faulty and the shell not retained firmly enough at the introduction location.

It is an object of the invention to obviate this disadvantage by providing a twin feed ammunition conveyor with two rotors and a forward distribution station in which the distribution station has conveying means for ensuring the accurate movement of each shell from its standby location to its introduction location and for retaining such shell firmly once it has arrived at the intro duction position.

According to the present invention, there is provided a twin feed ammunition conveyor for feeding an automatic weapon from one or other of two strips of shackled shells, which conveyor comprises: two star wheel rotors having longitudinal axes disposed symmetrically on respective sides of a longitudinal plane of symmetry of the ammunition conveyor and extending through an extraction station, where the shells are separated from their shackles by a longitudinal forward displacement, and through a forward distribution station comprising a central introduction location and two lateral standby locations disposed symmetrically on respective sides of the central introduction location and each for receiving from the extraction station a shell extracted from a respective one of the two strips of shells; conveying means associated with each of the two rotors in the distribution station for transferring a shell from the respective standby location to the central introduction location, and a selector mechanism enabling the gunner at his choice selectively to couple one or other of the two rotors to a common drive device actuated by a mobile part of the weapon; in which conveyor each conveying means comprises at least one star wheel with 2n teeth so disposed on the respective rotor as to engage with a shell in the respective standby location, and

at least one set of n diametrical pushers keyed angularly to the respective rotor but free to slide parallel to their axes, each pusher having at its opposite ends shoes which bear, over a portion of the rotary travel of the pusher, against a control. cam adapted to impart a sliding movement to the pusher, and, over another portion of the said rotary travel, against a shell during its transfer from the respective standby location to the introduction location, whereby the shell is constrained upon release from the star wheel of the conveying means to move into the introduction location where it is temporarily held by the shoe of the pusher involved in the transfer of the shoe and by the shoe of a pusher of the conveying means associated with the other rotor.

Preferably, the control cam of each conveying means comprises a fixed part disposed on the same side of the plane of symmetry as the respective rotor and a mobile part borne by a pivoting member disposed between the two fixed cam parts, such pivoting member being automatically displaced by the pushers of the driven rotor in the direction of the non-driven rotor.

An ammunition conveyor of this kind advantageously includes means adapted to introduce correctly into the weapon the last shell of the strip being fired, both if the other strip is exhausted or absent, or if such other strip is in place with shells engaged by the corresponding rotor.

As a rule the rotor-driving device is a conventional pawl-type driving system which prevents the rotors from returning during normal operation, a dog clutch system, when in a neutral position, enabling the rotors to be turned back for the removal of the strips of shells.

In these conditions the rotor which is not being driven (whether or not it is connected to shells) is always locked against rotation at the dog clutch device, and the shoe against which the shell bears in the introduction position is immobile.

Having regard to the foregoing, and according to a special feature of the invention, the means adapted to ensure the correct introduction of the last shell is formed by a retaining pawl disposed centrally in the distribution station for movement on a pivot having an axis parallel to that of the shells and subjected to the action of resilient return means tending to retain such pawl in a central vertical position, a lower arm of such pawl being so disposed as to be repelled by the shell arriving in the introduction position thereby to move an upper arm of the pawl into a position in which it locks the driven rotor.

In these conditions the last shell arriving at the introduction position is firmly retained in orientation by an immobile shoe of the non-driven rotor and by a shoe of the driven rotor, the latter shoe then also being immo bilized because the driven rotor is temporarily locked by the retaining pawl.

In a preferred embodiment of the invention, a forward part of each rotor disposed in the distribution station comprises, as the conveying means, two spacedout coaxial star wheels between which pairs of diametrical pushers are disposed, the corresponding ends of the pushers of each pair being connected by a longitudinal shoe subjected at central region thereof to the action of the control cam which is orientated transversely and disposed in an upper region of the distribution station.

In order that the invention may be readily understood, an embodiment thereof will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 illustrates diagrammatically, in plan with parts removed, a preferred embodiment of a twin feed ammunition conveyor with a forward distribution station according to the invention;

FIG. 2 is a cross-section, taken along the line lI-II in FIG. 1; and

FIGS. 3 to are diagrams illustrating the most characteristic successive operational phases of the twin feed ammunition conveyor embodying the invention.

The twin feed ammunition conveyor illustrated in FIG. 1 is suitable for an automatic weapon (for in stance, an automatic mm gun) of the open breech type, that is, the type in which, if firing stops, the mobile breech l of the weapon is retained in a rearward position from which, when firing is resumed, it performs a forward closure movement the effect of which is to introduce into the shell chamber 2 of the weapon a shell disposed in an introduction position, and then to fire the shell.

The ammunition conveyor comprises an extraction station E in which there engage laterally, on respective sides of the longitudinal plane of symmetry of the ammunition conveyor, two separate strips of shells, namely a left-hand strip A and a right-hand strip B, the purpose of the extraction station being to extract from its shackle the upstream end shell of the strip of shells in use by a longitudinal displacement imparted to such shell by one or other of two lateral pushers 1a, 1b disposed behind the mobile breech 1. A distribution station D is disposed forwardly of the extraction station E and comprises two lateral standby locations arranged symmetrically on respective sides of a central introduction location disposed in line with the shell chamber 2 of the weapon. In FIG. 1 the two standby locations are occupied by two shells shown in chain lines, and the introduction location is occupied by a shell shown in solid lines, such illustration corresponding to a fictive situation which enables these locations to be identified in the distribution station D.

The way in which the extraction station E is constructed will not be described in detail. It can be constructed in any suitable manner, inter alia as indicated in the aforementioned French Pat. No. 1,572,169, and all that will be pointed out is that the extraction station comprises, firstly, two star wheel rotors 3a, 3b having longitudinal axes disposed symmetrically on respective sides of the longitudinal plane of symmetry of the ammunition conveyor, such rotors being extended forwardly through the distribution station D (in line with the standby locations) and comprising, in the extraction station E, star wheels (not shown) cooperating with the strip of shells A or B disposed on the same side and, secondly, a selector mechanism, of which only the actuating member 4 is shown, enabling one or other of the rotors 3a, 3b to be coupled as required to a common driving device actuated by a mobile part of the weapon, such actuating member 4 being able to occupy either a central position in which the two rotors are disengaged, a left-hand position (illustrated in FIG. 1) in which the rotor 3a is engaged, or a right-hand" position in which the rotor 3b is engaged.

The distribution station D, whose internal elements are shown in plan in FIG. 1 and in cross-section in FIG. 2, comprises conveying means adapted to transfer one of the shells coming from the strip of shells A or B in use from the standby position to the introduction position.

To this end, according to the preferred embodiment of the invention, the conveying means comprise, for each rotor 3a, 3b, two star wheels 5a, 5b longitudinally spaced apart and keyed to that part of the corresponding rotor 3a, 3b which extends through the distribution station, each of the star wheels comprising an even number of teeth, for instance, four teeth, the pair of star wheels 5a being adapted to mesh with a shell coming from the strip A into the standby position, while the pair of star wheels 5b is adapted to mesh with a shell coming from the strip B into the standby position. Disposed between the star wheels of each pair is a set of diametrical pushers which number half the number of the teeth of the star wheels. In the illustrated embodiment, two diametrical pushers 6a are provided for the rotor 3a and two diametrical pushers 6b are provided for the rotor 3b. The pushers 6a, 6b have at their opposite ends shoes (7a in the case of pushers 6a, and 7b in the case of pushers 6b) which bear, over a certain sector of their rotary travel, against a control cam 8a or 8b adapted to impart a sliding movement to the corresponding pushers 6a or 6b and, over another sector of such rotary travel, against the flange of a shell in course of transfer from its standby position to its introduction position.

When the shell is actually in the introduction position, as is the case with the shell C in FIG. 2, it bears against the lips of the introduction corridor and is temporarily (i.e. until it is seized and introduced by the mobile breech l) locked by the shoe 7a which has transferred the shell and by the shoe 7b (symmetrical with the preceding one) of the rotor 3b not in use.

In this embodiment each rotor has two sets of sliding pushers offset at an angle of 90 in relation to one another, each set being formed by two parallel pushers (6a or 6b) having their ends connected by two shoes (7a or 7b) which are diametrically opposed.

To save space and give the moving members room to move, the control cams 8a, 8b comprise a fixed part disposed in the upper region of the distribution station D, such fixed part being continued, in the direction of the central region of the distribution station D, by a camway borne by a pivotable member 9 articulated on a fixed pivot, the edges of the pivotable member forming the two camways respectively continuing the fixed parts of the control cams 8a, 812.

When the ammunition conveyor is in operation, the pivotable member 9 is repelled, by the shoe 7a or 7b of the rotor 3a or 3b in use, into an inclined position in which the camway of the pivotable member continues the fixed part of the corresponding control cam 8a or 8b without a gap.

To make sure that the shell in the introduction position C is satisfactorily retained in that position when the rotor in use has come to its last shell i.e., when such rotor is freely rotatable and is therefore incapable of contributing by one of its shoes to the temporary locking of the shell in the introduction position a retaining pawl 10 is provided. This pawl 10 is disposed in the central region of the distribution station D, is articulated on an axis parallel with the shells, and is subjected to the force of a return spring 1 l urging the pawl 10 in the direction of a central position. Under the action of the body of the shell arriving in the introduction position, the pawl 10 is displaced to an inclined position (illustrated in FIG. 2) in which the pawl 10 bears via its upper arm against an arm of the star wheel of the rotor in use, which is thus temporarily locked. The shoe 7a in contact with the shell in the introduction position is then immobilized and locks the shell in the introduction position until the start of its introduction phase. Once the shell C has been introduced into the shell chamber 2 of the weapon, the retaining pawl 10 resumes its central position under the action of its return spring 11.

The main successive phases occurring during the operation of the double feed ammunition conveyor described above will now be described with reference to the diagrams (FIGS. 34) which show the mobile breech l (in the open or closed position) and in which the successive shells of two strips of shells A and B are denoted by the references A,, A and B B respectively.

FIG. 3 shows the weapon in an empty condition with the breech 1 open and the selector 4 in the neutral position, one of the strips of shells, for instance, the strip B whose shells B and B are shown, being engaged in the extraction station of the ammunition conveyor in a conventional manner, as is done with a single feed ammunition conveyor.

Starting from this situation, and without modifying anything at all, the gunner engages in the extraction station of the ammunition conveyor the strips of shells A whose shells A, and A are shown, the new situation, with the two strips of shells A and B engaged, being shown in FIG. 4.

The gunner then presses the trigger, thus releasing the breech l which, under the action of its return springs, performs its closure travel, the lateral pushers la, lb of the breech repelling the shells A B of the strips A, B into the standby position as shown in FIG. 5.

The gunner now makes a selection operation and, for instance, displaces the selecting member 4 towards the left if he wishes to fire first with shells from strip A (the situation illustrated in FIG. 6).

The gunner then re-arms the breech 1 whose return travel makes the shell A move out of its standby posi tion into its introduction position (by means of the conveying means associated with the rotor 3a in the distribution station) and causes a forward movement by one step of the strip A whose shell A enters the extraction station, followed by the shell A (the situation illustrated in FIG. 7).

The gunner the presses the trigger and the breech l returns to the closure position, introducing and firing the shell A and repelling the shell A into the standby position, as shown in FIG. 8.

The return travel of the breech 1, following on the firing of the shell A causes the shell A to move into the introduction position and advances the strip of shells A by one step, the situation then being that illustrated in FIG. 9, supposing that the breech 1 has been retained in the open position i.e., that the gunner has proceeded to single round firing.

The gunner can then either resume firing with the strip of shells A, or, if he wishes to take shells from strip B, displace the selecting member 4 towards the right, as shown in FIG. 10, the result of the start of firing being then at the first shot to introduce and fire the shell A and move the shell A into the standby position and, during the following shots, to make the shells of strip B move by a process identical to that set forth hereinbefore for firing the strip of shells A.

We claim:

1. A twin feed ammunition conveyor for feeding shells to a shell chamber of an automatic weapon, such conveyor including:

a structure having a longitudinal plane of symmetry;

means defining in said structure an extraction station for receiving on respective sides of the plane of symmetry of said structure first and second strips of shells in which the shells are retained by shackles;

means operative at said extraction station for individually separating the shells of the first and second strips from their shackles by a longitudinal forward displacement of the shells;

means defining in said structure a distribution station disposed forwardly of said extraction station;

said distribution station having a central introduction location from which the shells are fed to the shell chamber of the weapon, and first and second standby locations disposed symmetrically on respective sides of said central introduction location for receiving shells displaced forwardly from said extraction station;

first and second conveying means in said distribution station for transferring shells respectively from said first and second standby locations to said central introduction location;

said first and second conveying means comprising respective first and second rotors having longitudinal axes disposed symmetrically on respective sides of the plane of symmetry of said structure and extending through both said extraction and distribution stations;

common drive means for driving said first and second rotors; and

selector means operable by a user to selectively couple said first and second rotors to said common drive;

in which ammunition conveyor the improvement comprises said first and second conveying means further comprising:

at least one star wheel having 2n teeth on each of said first and second rotors for transferring a shell from said first and second standby locations respectively towards the central introduction location;

at least one set of n radially extending pushers on each of said first and second rotors;

each said pusher being keyed angularly to the respective rotor and being slidable in the radial direction;

first and second control cams defined in said structure in said distribution station for imparting a radial sliding movement to said pushers on rotation of said first and second rotors respectively; and

a shoe on each end of each said pusher for following the respective control cam over one portion of the rotation of the respective rotor;

each said shoe being operative, over another portion of the rotation of the respective rotor, to engage a shell being transferred towards the central introduction location by the respective star wheel to positively introduce the shell into the central introduction location where the shell is retained by said shoe and by the shoe of a pusher on the other rotor.

2. An ammunition conveyor as claimed in claim 1,

wherein said first and second cams comprise respective first and second fixed cam parts in said structure and a pivotable member defining respective first and second mobile cam parts, said pivotable member being disposed between said first and second cam parts for displacement towards one of said first and second rotors by the pushers of the other of said rotors upon rotation of said other rotor.

3. An ammunition conveyor as claimed in claim 1, comprising: a pivot parallel to the plane of symmetry of said structure and disposed centrally in said distribution station; a retaining pawl mounted intermediate its ends on said pivot to define a lower pawl arm and an upper pawl arm; resilient return means biasing said pawl into a central vertical position in said distribution station; said lower pawl arm being disposed so as to be repelled by a shell transferred into the central introduction location by either of said first and second conveying means whereby to move said upper pawl arm into locking engagement with the rotor of the conveying means which effected the transfer of the shell.

4. An ammunition conveyor as claimed in claim 1, wherein said first and second conveying means comprise: two axially spaced co-axial star wheels on each of said first and second rotors; and a plurality of angularly spaced pairs of pushers disposed on each said rotor between said two star wheels; each said shoe comprising an axially extending elongated member connecting corresponding ends of the pushers of a said pair; each of said first and second control cams being orientated transversely of the respective rotor in an upper region of said distribution station for engagement by a portion of said elongated shoe members intermediate the ends of said shoe members.

5. An ammunition conveyor as claimed in claim 3, wherein said first and second conveying means comprise: forward and rear coaxial star wheels axially spaced on each of said rotors; said pushers being disposed on each said rotor between said forward and rear star wheels; said retaining pawl being disposed in said distribution station for co-operation with said rear star wheel of each said rotor. 

1. A twin feed ammunition conveyor for feeding shells to a shell chamber of an automatic weapon, such conveyor including: a structure having a longitudinal plane of symmetry; means defining in said structure an extraction station for receiving on respective sides of the plane of symmetry of said structure first and second strips of shells in which the shells are retained by shackles; means operative at said extraction station for individually separating the shells of the first and second strips from their shackles by a longitudinal forward displacement of the shells; means defining in said structure a distribution station disposed forwardly of said extraction station; said distribution station having a central introduction location from which the shells are fed to the shell chamber of the weapon, and first and second standby locations disposed symmetrically on respective sides of said central introduction location for receiving shells displaced forwardly from said extraction station; first and second conveying means in said distribution station for transferring shells respectively from said first and second standby locations to said central introduction location; said first and second conveying means comprising respective first and second rotors having longitudinal axes disposed symmetrically on respective sides of the plane of symmetry of said structure and extending through both said extraction and distribution stations; common drive means for driving said first and second rotors; and selector means operable by a user to selectively couple said first and second rotors to said common drive; in which ammunition conveyor the improvement comprises said first and second conveying means further comprising: at least one star wheel having 2n teeth on each of said first and second rotors for transferring a shell from said first and second standby locations respectively towards the central introduction location; at least one set of n radially extending pushers on each of said first and second rotors; each said pusher being keyed angularly to the respective rotor and being slidable in the radial direction; first and second control cams defined in said structure in said distribution station For imparting a radial sliding movement to said pushers on rotation of said first and second rotors respectively; and a shoe on each end of each said pusher for following the respective control cam over one portion of the rotation of the respective rotor; each said shoe being operative, over another portion of the rotation of the respective rotor, to engage a shell being transferred towards the central introduction location by the respective star wheel to positively introduce the shell into the central introduction location where the shell is retained by said shoe and by the shoe of a pusher on the other rotor.
 2. An ammunition conveyor as claimed in claim 1, wherein said first and second cams comprise respective first and second fixed cam parts in said structure and a pivotable member defining respective first and second mobile cam parts, said pivotable member being disposed between said first and second cam parts for displacement towards one of said first and second rotors by the pushers of the other of said rotors upon rotation of said other rotor.
 3. An ammunition conveyor as claimed in claim 1, comprising: a pivot parallel to the plane of symmetry of said structure and disposed centrally in said distribution station; a retaining pawl mounted intermediate its ends on said pivot to define a lower pawl arm and an upper pawl arm; resilient return means biasing said pawl into a central vertical position in said distribution station; said lower pawl arm being disposed so as to be repelled by a shell transferred into the central introduction location by either of said first and second conveying means whereby to move said upper pawl arm into locking engagement with the rotor of the conveying means which effected the transfer of the shell.
 4. An ammunition conveyor as claimed in claim 1, wherein said first and second conveying means comprise: two axially spaced co-axial star wheels on each of said first and second rotors; and a plurality of angularly spaced pairs of pushers disposed on each said rotor between said two star wheels; each said shoe comprising an axially extending elongated member connecting corresponding ends of the pushers of a said pair; each of said first and second control cams being orientated transversely of the respective rotor in an upper region of said distribution station for engagement by a portion of said elongated shoe members intermediate the ends of said shoe members.
 5. An ammunition conveyor as claimed in claim 3, wherein said first and second conveying means comprise: forward and rear coaxial star wheels axially spaced on each of said rotors; said pushers being disposed on each said rotor between said forward and rear star wheels; said retaining pawl being disposed in said distribution station for co-operation with said rear star wheel of each said rotor. 